RFR: 6506405: Math.abs(float) is slow [v2]

[Andrew Haley]

On Thu, 8 Jul 2021 01:05:16 GMT, Brian Burkhalter <bpb at openjdk.org> wrote:

>> Please consider this change to make the `float` and `double` versions of `java.lang.Math.abs()` branch-free.
>
> Brian Burkhalter has updated the pull request incrementally with one additional commit since the last revision:
> 
>   6506405: Add comments, use new consts for masking

Moves between GPRs and FPRs are often slow. There's a 10-cycle latency on some AArch64, so we avoid it whenever we can. Mind you, we don't care about this patch because we always generate FABS from an intrinsic anyway.

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PR: https://git.openjdk.java.net/jdk/pull/4711